This invention generally relates to cathode ray tubes and, more particularly, to a microphonic damper clip for a tension mask in a cathode ray tube (CRT).
A color picture tube includes an electron gun for forming and directing three electron beams to a screen of the tube. The screen is located on the inner surface of the faceplate panel of the tube and comprises an array of elements of three different color emitting phosphors. An aperture mask, which may be either passive, i.e., a shadow mask or active, i.e., a focus mask, is interposed between the gun and the screen to permit each electron beam to strike only the phosphor elements associated with that beam. The aperture mask is a thin sheet of metal, such as steel, that is contoured to somewhat parallel the inner surface of the tube faceplate. An aperture mask may be either formed or tensioned.
A tension mask is stretched over a strong, specially shaped frame to form a sector of a cylindrical surface or may alternatively be shaped to form a substantially flat mask. The tension ensures that the apertures formed on the mask remain in alignment with the phosphor elements on the screen. This design has a disadvantage that the mask is subject to vibration from external sources (e.g., speakers near the tube) otherwise known as microphonics. Such vibration varies the positioning of the apertures through which the electron beam passes, resulting in visible display fluctuations. Ideally, these vibrations need to be eliminated or, at least, mitigated to produce a commercially viable television picture tube.
The present invention provides vibration damper clips attached to a border of a tension mask. The vibration damper clips are formed of two halves with each half having a first and second leg. The first leg from each half is inserted into a respective aperture disposed on the border of the tension mask. Each half is rotated, where each first leg abuts each other. The first legs are then attached to one another. When joined, both halves form a damper clip for damping the vibrations subjected to the tension mask.